茜草科是双子叶植物龙胆目下的一个科。早期的分类系统（克朗奎斯特分类法）将茜草科分类在茜草目内。而近期的分类系统（APG II 分类法）则是将茜草科分类在龙胆目内，且将离瓣茜草科、Henriqueziaceae、乌檀科、纤花草科并入到茜草科内，新的茜草科有600多属，10000种以上，中国大约有80属500余种，多数分布在南方。本科植物分为三个亚科：

本科的茜草属、栀子属可以做染料，咖啡可以做饮料，金鸡纳属、猪殃殃属、蔓虎刺属、檄树属、钩藤属可以做药用植物，仙丹花属、玉叶金花属、寒丁子属可以做观赏植物。

The Rubiaceae are a family of flowering plants, commonly known as the coffee, madder, or bedstraw family. It consists of terrestrial trees, shrubs, lianas, or herbs that are recognizable by simple, opposite leaves with interpetiolar stipules. The family contains about 13,500 species in 611 genera, which makes it the fourth-largest angiosperm family. Rubiaceae has a cosmopolitan distribution, however, the largest species diversity is concentrated in the (sub)tropics. Economic importance includes Coffea, the source of coffee, Cinchona, the source of quinine used to treat malaria, some dye plants (e.g. Rubia), and ornamental cultivars (e.g. Gardenia, Ixora, Pentas).